Pen



FIG. 1 is a top, front and side perspective view of a pen showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof from the right of FIG. 2, the side elevational view from the left of FIG. 2 being a mirror image thereof;

FIG. 4 is rear elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a pen, as shown in and described. 